1. Field of the Invention
The present invention relates to cable clamps for use with electrical distribution panels, outlet boxes, load centers, or the like, which are commonly used in campers, mobile homes, or other recreational vehicles to branch a main electrical current to various auxiliary devices.
2. Background Art
A variety of devices are used to secure electrical cables in the branch circuit apertures of electrical distribution panels. These cables are typically of rounded rectangular shape with nonmetallic insulation sheathing surrounding a pair of metallic wires. The distribution panel housings are typically made of non-conductive polymer material. Typically, the apertures in electrical distribution panels through which the cables are inserted are formed with removable plastic windows, or "knock-outs", which temporarily cover the apertures until they are removed to allow insertion of electrical cables.
Clamping electrical cables in the apertures or knock-outs of electrical distribution panels in a manner that they cannot be easily pulled out or dropped into the outlet box is highly desirable for practical purposes, and is required by various industry codes. Conventionally, in the housing of an electrical distribution panel, electrical cables are secured by a variety of clamp-type or other devices. Some examples include molding cable clamps integrally with the electrical distribution panel housing; internal clamps comprising a single piece of material, such as an internal wedge member, for grasping the cable and which is incapable of moving through the knock-out opening; or forming the knock-outs with closure panels which remain connected to the interior walls of the knock-out opening and bear against the cable after insertion to hold the cable within the knock-out opening.
Some disadvantages encountered with conventional devices for securing the cables within the knock-outs of electrical distribution panels include the necessity of molding such devices within or contemporaneously with the panels, increasing the expense and complication of tooling and manufacture. In addition, many conventional devices frequently require additional tools or screwing steps for insertion of the cables. The integral serrations or "teeth" of conventional devices which secure the cable can cut into the insulation around the cable wire, which can compromise the conductivity of the cable by partially striping the cable insulation from the metallic wire when pulling strain is applied to the cable. Finally, many conventional cable clamps are specifically configured for securing cables of a single diameter size or gauge within the knock-out opening.